title: Shape-memory properties and degradation behavior of multifunctional electro-spun scaffolds.
abstract: Multifunctional polymer-based biomaterials, which combine degradability and shape-memory capability, are promising candidate materials for the realization of active self-anchoring implants. In this work we explored the shape-memory capability as well as the hydrolytic and enzymatic in vitro degradation behavior of electro-spun scaffolds prepared from a multiblock copolymer, containing hydrolytically degradable poly(p-dioxanone) (PPDO) and poly(e-caprolactone) (PCL) segments, which we have named PDC. Electro-spun PDC scaffolds with an average deposit thickness of 80 ± 20 µm and a porosity in the range from 70% to 80% were prepared, where the single fiber diameter was around 3 µm. Excellent shape-memory properties were achieved with high recovery rate (Rr) values in the range of Rr = 92% to 98% and a recovery stress of smax = 4.6 MPa to 5.0 MPa. The switching temperature (Tsw) and the characteristic temperature obtained under constant strain recovery conditions (Ts,max) were found in the range from 32 °C to 35 °C, which was close to the melting temperature (Tm,PCL) associated to the poly(e-caprolactone) domains. A linear mass loss was observed in both hydrolytic and enzymatic degradation experiments. The mass loss was substantially accelerated, in enzymatic degradation when Pseudomonas cepacia lipase was added, which was reported to accelerate the degradation of PCL. During hydrolytic degradation a continuous decrease in elongation at break (eB) from eB = 800% to 15% was observed in a time period of 92 days, while in enzymatic degradation experiments a complete mechanical failure was obtained after 4 days.
authors.affiliation: Center for Biomaterial Development and Berlin-Brandenburg Center for Regenerative Therapies, Institute of Polymer Research, Helmholtz-Zentrum Geesthacht, Teltow, Germany.
authors.forename: Karl
authors.initials: K
authors.lastname: Kratz
authors.forename: Ronny
authors.initials: R
authors.lastname: Habermann
authors.forename: Tino
authors.initials: T
authors.lastname: Becker
authors.forename: Klaus
authors.initials: K
authors.lastname: Richau
authors.forename: Andreas
authors.initials: A
authors.lastname: Lendlein
mesh_terms: D001672:Biocompatible Materials; D016956:Burkholderia cepacia / Q000201:enzymology; D004146:Dioxanes / Q000737:chemistry*; D006868:Hydrolysis; D008049:Lipase / Q000737:chemistry / Q000302:isolation & purification; D010316:Particle Size; D011091:Polyesters / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D016062:Porosity; D013499:Surface Properties; D013718:Tensile Strength; D013997:Time Factors; D054457:Tissue Scaffolds; D044366:Transition Temperature
chemical_list: D001672:Biocompatible Materials; D004146:Dioxanes; D011091:Polyesters; D011108:Polymers; C016240:polycaprolactone; C079733:poly-4-dioxan-2-one; D008049:Lipase